Sound control system for steel roof decks

Abstract

A steel roof deck diaphragm to provide structural rigidity to a building wherein loads of varying intensity can cause movement of structural members, which tends to generate noise when two members rub or work against each other. Corrugated sheets of high tensile steel are supported from below and span the distance between purlins, the corrugated sheets having over-lapping side edges and end edges and upper and lower surfaces. Non-metallic strips of felt form spacers positioned between the over-lapping side edges and end edges to prevent generation of noise resulting from relative movement of the corrugated sheets.

Description

A steel roof deck diaphragm having non-metallic spacers between over-lapping side edges and end edges of steel sheets to prevent noise resulting from relative movement of the sheets and resilient cushions between the steel sheets and supporting purlins.BACKGROUND OF INVENTIONRoof deck systems, composed of a high tensile steel base with thermal insulation and high performance mineral board mechanically anchored to the steel sections, provide composite strength. The resultant assembly is a strong, durable substrate for roofing applications. Composite roof deck assemblies are disclosed in U.S. Pat. No. 4,601,151; U.S. Pat. No. 4,736,561; U.S. Pat. No. 4,707,961; U.S. Pat. No. 4,783,942 and U.S. Pat. No.: 5,584,153.Corrugated steel sections are positioned over structural supports and anchored in place with welded connections through special weld washers, of the type disclosed in U.S. Pat. No. 4,601,151, or with mechanical fasteners. Thermal insulation, available in a variety of types an...

AI Technical Summary

Benefits of technology

We have found that by isolating the steel deck sections from contact with all steel surfaces, the noise created by deck movement could be eliminated. We placed sound deadening material such as a heavy felt, between the supporting structure and the steel sheets, so that the steel roof deck sheets did not touch the steel supporting structure. Further, deadening felt was positioned between each side lap and end joint of the steel sheets, so that the steel sheets did not touch each other, even though they are side lapped one full corrugation and end lapped about three inches.

After completing the assembly, with all screws, etc. installed, the roof deck was tested for sound and found it to be sound free. The popping sound was eliminated by isolating the steel from direct contact with any other component.

The method and apparatus disclosed herein preferably includes non-metallic spacers positionable between adjacent edge and end surfaces of sheets of formed steel to prevent rubbing between adjacent surfaces resulting from expansion or contraction of the sheets. The spacer is sufficiently resilient to permit limited relative movement of adjacent surfaces, but sufficiently rigid and of a thickness which does not permit sufficient movement to detract from the diaphragm strength of the roof deck. Thus, the spacers eliminate the need for insulated ceilings or other noise barriers in the facility.

Problems solved by technology

As the insulation thickness increases the length of the threaded fasteners increases, creating potential rotation and bending problems for the fasteners.

As a result, the thickness of the insulation is limited by the threaded fastener length.

Additionally, since fasteners typically extend all the way through the roofing layers from the exterior of the roof to the interior supporting structure of the roof, thermal shorts may be created between the exterior of the roof and the interior of the roof, which is undesirable in extremely hot or cold climates.

Thermal expansion and contraction of the steel sheets and the steel purlins can cause movement of adjacent surfaces, which generates noise when the surfaces rub or work against each other.

Expansion and contraction creates noise at the juncture between edges and ends of the sheets and between the lower surface of the sheets and upper surfaces of the purlins which support them.

However, when the insulated ceiling is eliminated, unwanted noise may become a problem.

For example, in the sanctuary of a church, constructed without a ceiling, in a hot sunny climate, thermal expansion of steel sheets in the roof deck may result in excessive noise during church services.

The noise is particularly noticeable during prayer or other periods of silence.

It has been reported that under certain conditions and at particular times of the year, ministers had trouble conducting services because of the popping and crackling noises emanating from the roof deck.

Movement of the steel deck section within the assembly produced popping noises.

Additionally, friction between the top of the steel section and components, such as thermal insulation or mineral board, laid directly on top of the steel also produce noise.

The supporting steel moves under thermal changes and causes movement of the steel decking, which causes noises or popping.

The popping noise is generated at the contact points between the steel deck and the steel supporting structure.

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